Terahertz-Radiation Photomixers on Nitrogen-Implanted GaAs

The authors have fabricated and characterized photomixers based on high energy nitrogen-ion-implanted GaAs. For material optimization and annealing dynamics in MSM photodetector structures, 400 keV implantation energy was used with an ion dose of 1times10¹⁶ cm^-2 . For photomixer structures, 3 Me V energy was used to implant N ⁺ ions into GaAs substrates, with an ion concentration dose of 3times10¹² cm^-2. The N⁺-implanted GaAs photomixers exhibit improved output power in comparison to their counterparts, photomixers fabricated on low-temperature-grown GaAs. The highest output power was 2.6 muW at 850 GHz and about 1 muW at 1 THz. No saturation of the output power with increased bias voltage and optical input power was observed. These characteristics make N⁺ -implanted GaAs the material of choice for efficient high power sources of terahertz radiation